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Патент USA US2118266

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May 24, 1938.
2,118,266
c. H. NORDELL
SEWAGE TREATMENT
Filed June 29, 1956
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New
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2,118,266
rPatented May 24, 1938
UNITED- STATES’ - PATENT
OFFICE’
2,118,266
SEWAGE TREATMENT
' Carl H. Nordell, Chicago, 111., assignor to Advance
Engineering Company; Chicago, 111., a corpora-,
tion of Illinois
Application June 29, 1936, Serial No. 87,885
4 Claim. (CL- 210-8)
This invention relates to ‘the treatment ,of. ditioned state becomes immediately available for
sewage, and particularly. to the treatment of
sewage with the so-called activated sludge process
' in which the ‘incoming sewage is mixed with
sludge resulting from the process and the mixed
liquid is subjected to aeration.
_ J
In all sewage'treatment systems the amount of
sewage to be treated and the strength or concen
tration of the sewage is subject to very considere
10 able ?uctuations. Rainstorms cause consider
able changes of volume and-strength in the case
_of combined surface water-and sewage systems.
Changes in volume and strength occur periodical
sewage aeration when a peak load needs to be
treated. Conversely, when a weak or light oxida
tion load .is being received and a charge of pre
conditioned sludge is being accumulated, only
part of the aerating tank system may be used for
sewage treatment, a condition which is particu
larly adapted for e?icient operation.
,The invention will more fully be understood
from the following description of- a preferred 10
,method' of- operation as practiced in a suitable
apparatus illustrated in the accompanying draw
ing in which;
Figure 1 is a diagrammatic sectional plan view
Thus, during any twenty-four hour period
of
a sewage treatment apparatus, and
the
strength
of
sewage
varies
within'
very
wide
15
Fig. 2 is a sectional detail view taken on the
limits. During the night and early morning the
‘
incoming flow may be mainly water which drains l line 2--2 of Fig. 1.
Referring to the drawing, the main aeration
from the ground into the sewers. In the fore
tanks are indicated by the reference numerals I0.
noon the amount of excreta collected by the sys
tem may attain peak proportions. Another factor These tanks are'connected in series and are ar
which may give a peak load of short duration is ranged alongside each other.. It will be under
ly.
the delivery of trade wastes into the sewage sys
tem.
..
>
In my copending application, Serial No. 41,741,
?led September23, 1935, I have described and
claimed a method‘ of controlling the air supply
for the effective treatment of sewage of any pre
vailing strength and rate of supply.
The present invention relates primarily to a
30 method in which the sludge admixed with the
sewage ispreconditioned and controlled. Thus,
generally stated in times of low load I accumulate
a charge of sludge and maitnain it at a high de
gree .of e?iciency by supplying an ‘appropriate
amount of air thereto. In the preferred manner
of operation I pass sludge continuously from the
accumulating mass into admixture with the in
coming sewage. When the sewage becomes
stronger I may supply an extra quantity of sludge
40 to the‘incoming sewage.
This extra quantity I
deliver over a period of time‘ or practically im
mediately depending upon- the nature of the
change in the strength of the sewage. Thus, in
the event of a daily periodic peak load of several
45 hours’ duration I add the extra quantity of pre
conditioned supply of sludge gradually over
several hours of time.
In the case of a sudden
change of strength due to the dumping of a
' large amount of trade wastes into the sewage sys
tem, the additional amount of sludge may be
brought 'into the aeration system practically in
stantaneously.
stood that this location of ' aeration tanks is
merely one conventional arrangement which may
.
‘
One of the important advantages of my new
method lies in the fact that the tank in which
55 the sludge is accumulated and held in precon
be employed.
.
'
,
Each tank I0 is provided with a suitable aerator 25
II which maybe supplied with compresed air
from a pipe I2, the supply to each aerator being
controlled by valve l3 in the branch supply pipes
|4_
.
.,
,
An auxiliary tank I5 is provided which dis
30
charges into the inlet end of the first tank I0
through an opening IS. The tank I5 is provided
with a suitable aerator II, which is supplied with
air from a pipe I8, the supply being controlled by
35
a valve 19.
The treated sewage passes from the outlet end
of the last tank I0 through a pipe 20 to a settling
tank 2|. I E?luent flows out of this tank by the
over?ow pipe 22. Sludge is“ drawn from the
bottom of the settling tank 2| by pump 23 and is 40
passed by pipe 24 to the inlet end of the tank IS.
A suitable amount of sludge may be withdrawn
continuously, or from time to time, by means of
a pipe 25, and the amount of sludge in the system
may be controlled by means of the valve 26.
The tank l5 may be provided with one or more
partitions 21 and 28 which separate it effectively
into a plurality of compartments 29, 30 and 3|,
‘for example. The partitions 21 and 28 are pro
vided with suitable openings 32, which are of
adequate size to enable the sludge to ?ow from
the inlet to the outlet end of the tank l5, while
small enough to avoid any objectionable degree
of ?ow in the opposite direction. The partition
21 is shown as permanently installed. The par 55
2
.
2,118,866
tition 28 is movable along the tank being pret
~ erably supported from a beam 33 which may
rest upon the upper tank walls, as shown in Fig. 2.
The sewage is supplied by the pipe 34. The
pipe 34 is connected by valved branch pipes 35,
36, 31 and 38, to the inlet end of the first tank
I ll, and to the compartments 3|, 30, and 29, re
spectively.
I
.
.
,1
‘
I
v
In the normal operation of the-process, sludge
10 is accumulated in the tank l6 and is maintained
_
-
I‘
>
.
determined in the manner and with the apparatus described in my copending patent applica
tions Serial No. 41,751‘?led September 23, 1935
and Serial No. 41,750 ?led September 23, 1935.
Having thus described my invention, what, I 6
claim as new and desire to secure by Letters Pat
ent of the United States is:
I
1. The method of treatingvsewage which com
prises subjecting sewage to aeration in an aerat
ing zone, separating activated sludge from the
preconditioned or in a highly active state by the , , treated sewage, returning a portion of said sludge ‘
expedient of subjecting it to a suitable degree
of aeration by air supplied by pipe l8.v Thus,
when the incoming sewage is “scant or weak,
15 it is delivered through the pipe 35 directly into
the tanks Ill. The sludge supplied'by the pump
23 builds up in the compartments 29, 30 and 3|,
a certain amount passing continuously through
the opening l6 into the ?rstptank M, where it is
20 admixed with the incoming sewage. The quan
tity of sludge builds up in the tank l5 until a
static condition is attained, as much sludge pass
ing out of the tank l5 as enters it. This grad
ual increase of sludge supply to the aeration
25 tanks may, in some cases, be arranged to take
care of certain diurnal changes of'quantity and
strength 0! the incoming sewage. When a peak
load is being received the amount of sludge nec
essary for the eii'ective treatmentol' the sewage
80 is very high and all or a part 01' the sewage
is diverted by one or more_of the pipes 36, 31
and 38 into the tank l5. It will be seen that a
small supply of sewage into one of these pipes
will give an immediate corresponding increase
to the sludge supplied to the reaction chambers
Ill through the opening l6. It a very heavy
peak load arrives, due, for example, to the sud
den discharge of a large amount of trade waste
into the sewage system, all the sewage may be
40 diverted into the tank l5. Thus, the whole sew
age supply may be diverted into the compart
ment 3 I, with the result that all the sludge there
in is immediately thrown into use. When this
is done the compartment 3| serves as an aerating
tank and thus temporarily augments the aera
tion capacity of the system at the time that an
increase of capacity is urgently needed. This
procedure may be repeated successively with the
other compartments 30 and 29, with the result
60 that the whole reserve supply of preconditioned
sludge and the whole reserve aeration space of
the tank I5 is throwninto action.
It will be understood that the amounts of air
supplied and the rate of‘ sludge supply will de
55 pend upon the volume of the incoming sewage
and its strength. These factors may readily be
to the aerating zone, accumulating a body of
activated, sludge in a preconditioning zone, and
diverting at least a part of the sewage into the
preconditioning zone‘ and thereby displacing a 16
quantity of sludge into the aerating zone.
'2. The method of treating sewage which com
prises subjecting sewage to aeration in an aerat
ing zone, separating activated sludge from the
treated sewage, passing said sludge to a pre— 20
conditioning zone communicating with said
aerating zone, and thereby displacing a corre
sponding ‘volume of activated sludge into said
aerating zone, and diverting at least a part of
sewage into said preconditioning zone andv there
by increasing the quantity of activated sludge
displaced into the aerating-zone.
-
3. The method of treating sewage which com
prises subjecting sewage to aeration in an aerat
ing zone, separating activated sludge from the
treated sewage, returning a part of said sludge
to the aerating zone, accumulating a body of
activated sludge in a preconditioning zone, di
verting at least a part of the sewage into the
preconditioning zone and thereby displacing a
further quantity of sludge into the aerating zone,
and thereafter diverting thesupply of sewage
directly into the aerating zone and accumulat
ing a new supply of sludge in the precondition
ing zone.
4. The method of treating sewage which com
prises subjecting sewage to aeration in an aerat
ring zone, separating activated sludge from the v
treated sewage, passing said sludge to a pre
conditioning zone communicating with said
aerating zone, thereby displacing a supply of
activated sludge into said aerating zone, divert
ing at least a part of sewage into said precon
ditioning zone and thereby increasing the quan
tity of activated sludge displaced into the aerat
ing zone, and thereafter'diverting the supply of
sewage directly into the aerating zone‘and ac
cumulating a’ new supply of sludge in the pre
conditioning zone.
CARL H. NORDELL.
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